Questions tagged [commutative-encryption]
A commutative encryption system allows a message encrypted with two different keys to be decrypted using the keys in either order.
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Software implementation of a commutative cipher?
I've got an application (detailed below) that calls for the use of a cipher that is commutative. I've been doing some googling & reading, and there are two algorithms that seem to get mentioned ...
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Are there any secure commutative ciphers?
This answer lists two commutative cipher algorithms - Pohlig-Hellman and SRA. However, they don't appear to be too secure.
My question is, here there any commutative ciphers out there that are secure ...
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Is Pohlig-Hellman Cipher the only option?
I am looking for a cipher which would allow something like this: E(E(M, a), b) = E(M, ab), where a and b are encryption keys, and ab is a combination of the keys that is impractical to separate into a ...
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Is there an encryption method where the order of decryption is irrelevant to the order of encryption?
With most encryption methods, if a message is encrypted first using key $k_1$ and then using $k_2$, to decrypt it you have to use first $k_2$ and then $k_1$.
I was wondering if there are any ...
Jihoon Chung
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Can we decrypt in this order when the message is encrypted twice?
If we encrypt a message twice with symmetric key $k_1$ first and then $k_2$ like $E_{k2}\{E_{k1}\{m\}\}$ , ideally we should decrypt with $k_2$ first and then $k_1$ but is it possible to decrypt with $...
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Commutative homomorphic encryption for zero-knowledge transfers
I am trying to design a scheme that would allow the following:
Alice has a number $a$ which she wants to keep secret
Bob has a number $b$ which he wants to keep secret
Alice can "transfer" a number ...
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How can Alice enable Bob to look-up values in a private map
I think this problem is similar to private set intersection, yet distinct in a way where:
Alice has an extensive Mapping of say id to name
id1 -> John Doe
id2 -> Jane Doe
id3 -> Edgar Poe
...
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Information sharing using interactive zero-knowledge system
I am trying to build a system that would allow information sharing in a kind of zero-knowledge way. Here is the set up:
Let's say there is a trusted third party that has Alice's sensitive info M (e.g....
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Can a commutative block cipher be indistinguishable from a random one, assuming a random permutation of keyspace?
Define a commutative block cipher with keyspace the finite set $K$, and message space the finite set $S$, to be an application
$$\begin{align}
E:K\times S&\mapsto S\\
(k,x)&\mapsto E(k,x)\text{...
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Can a commutative block cipher be indistinguishable from a random permutation, for fixed key?
Define a commutative block cipher with keyspace the finite set $K$, and data space the finite set $S$, to be an application
$$\begin{align}
E:K\times S&\mapsto S\\
(k,x)&\mapsto E(k,x)\text{ ...
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2way cryptography
Imagine Alice sending Bob a message. They act like this:
Alice encrypts a message with her key and sends it to Bob.
Bob encrypts the message again with his key and sends it back to Alice.
Alice ...
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Is there a system where multiple people can encrypt a message and then decrypt it in any order? [duplicate]
For example, A encrypts a message.
B encrypts that.
C encrypts that.
Then B decrypts, followed by A then C.
Are there systems that allow this? Does such a property have a name?
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